The present invention relates to surgical needles and more particularly to specially curved surgical needles especially advantageous for use in opthalmic microsurgery, and other microsurgery and the like.
Surgical needles can be any of a variety of shapes ranging from straight, to ski-shaped to curved. Curved needles are essential to most surgical procedures involving delicate or fine tissue to accurately locate the suture loop with a minimum of trauma to the tissue. To insert a curved needle, the surgeon must grasp the shaft of the needle with a needle holder at a point generally near the center of the needle or toward its butt to engage the tip in the tissue near the edge of the incision or wound. Then the suture is passed through the tissue and turned to pass through the tissue on the opposite side of the incision or would by a semi-rotational movement of the surgeon's fingers, wrist and forearm. The curvature of the needle helps establish for the surgeon the desired "bite " while the arcs of rotation of the surgeon's wrist and forearm or, more precisely, the arc of rotation of the needle holder held by the surgeon, establish the angulation (non-radiality) or non-angulation (radiality) of the suture across the incision or wound.
It is extremely important in certain microscopic surgery involving fragile tissue, such as in eye surgery or in anastomosis or other connection of fragile vessels or tubes, that the geometry of the path of the needle placing an appositional suture be uniform so as not to exert unequal or contrary forces parallel or tangential to the edge of the incision or would when the suture loop is formed and tied. This is important not only with individual (non-continuous) suturing but also when suturing using multiple continuous bites. For example, in a corneal transplant a continuous suture is made to define a series of isosceles triangles, so as not to induce undesirable rotative force between graft and recipient cornea.
Curved surgical needles, according to prior art construction, are curved in a single plane. As a surgeon observes them, particularly when through a vertically directed surgical microscope, and seeks to establish and maintain a precise arc of rotation for needle placement, he or she must be able to observe the location of the needle and when possible its point at all times during passage. To do this requires either that the head or visual axis be moved somewhat to one the side, impossible under a powerful microscope, or, alternatively, to tilt the plane of curvature of the needle, thereby altering the direction of penetration of the needle in the tissue.